The objective of this proposal is to isolate homogeneous populations of rat retinal cells, and then identify these cells morphologically and/or immunologically. Various biochemical parameters (particularly the presence of neurochemical transmitters and related enzymes) will be examined in the cells immediately after isolation and after short term culturing. This project will include: 1) Chemical dispersion of the rat retina and separation of cell types by centrifugation through a metrizamide density gradient. 2) Production of antibodies specific to the individual cell types in order to identify the cell type. 3) Assay procedures to measure various neurotransmitters and related enzymes, biologically active peptides, cyclic nucleotides, and neurotransmitter binding sites. 4) Short term culturing of the homogeneous cell populations.